Effect of vitamin C or beta-carotene on SCE induction by gamma rays in radiosensitized murine bone marrow cells in vivo.

The in vivo effect of vitamin C or beta-carotene on sister chromatid exchange (SCE) radio-induction was determined in murine bone marrow cells sensitized by BrdU incorporation. Pre- or post-treatment with 100 mg/kg body wt vitamin C did not cause a significant reduction in SCE induced by the exposure to 0.63 Gy gamma-rays. Treatment with a double dose of vitamin C and with 0.45 Gy radiation did not cause a significant reduction in SCE frequency. However, due to the fact that vitamin C per se is capable of SCE induction, if an additive effect of radiation and vitamin C is considered, the expected frequency is higher than that observed. This implies that vitamin C could have a slight radioprotective activity. With regard to beta-carotene, it has been demonstrated that 50 mg/kg body wt causes a statistically significant increase per se, although pre- and post-treatment with the same dose has an additive effect on SCE frequency induced by 0.62 Gy radiation. This indicates that beta-carotene does not have radioprotective activity under the conditions used in the present study.